Interleukin-23 (IL-23) is a heterodimeric cytokine comprised of two subunits, p19 which is unique to IL-23, and p40, which is shared with IL-12. The p19 subunit is structurally related to IL-6, granulocyte-colony stimulating factor (G-CSF), and the p35 subunit of IL-12. IL-23 mediates signaling by binding to a heterodimeric receptor, comprised of IL-23R and IL-12β1, which is shared by the IL-12 receptor. A number of early studies demonstrated that the consequences of a genetic deficiency in p40 (p40 knockout mouse; p40KO mouse) were more severe than those found in a p35KO mouse. Some of these results were eventually explained by the discovery of IL-23, and the finding that the p40KO prevents expression of not only IL-12, but also of IL-23. See, e.g., Oppmann et al. (2000) Immunity 13:715-725; Wiekowski et al. (2001) J. Immunol. 166:7563-7570; Parham et al. (2002) J. Immunol. 168:5699-708; Frucht (2002) Sci STKE 2002, E1-E3; Elkins et al. (2002) Infection Immunity 70:1936-1948).
Recent studies, through the use of p40 KO mice, have shown that blockade of both IL-23 and IL-12 is an effective treatment for various inflammatory and autoimmune disorders. However, the blockade of IL-12 through p40 appears to have various systemic consequences such as increased susceptibility to opportunistic microbial infections. Bowman et al. (2006) Curr. Opin. Infect. Dis. 19:245. Accordingly, specific blockade of the p19 subunit of IL-23 is preferred in the treatment of human disease because it interferes with the activity of IL-23 without interfering with the activity of IL-12.
Therapeutic antibodies may be used to block cytokine activity. A significant limitation in using antibodies as a therapeutic agent in vivo is the immunogenicity of the antibodies. As most monoclonal antibodies are derived from non-human species, repeated use in humans results in the generation of an immune response against the therapeutic antibody. Such an immune response results in a loss of therapeutic efficacy at a minimum, and potentially a fatal anaphylactic response. Accordingly, antibodies of reduced immunogenicity in humans, such as humanized or fully human antibodies, are preferred for treatment of human subjects. Exemplary therapeutic antibodies to IL-23p19 are disclosed in U.S. Patent Application Publication No. 2007/0009526, and in International Patent Publication Nos. WO 2007/076524, WO 2007/024846, WO 2007/147019, and WO 2009/043933 the disclosures of which are hereby incorporated by reference in their entireties. Additional humanized anti-IL-23p19 antibodies are disclosed in commonly assigned applications published as International Patent Publication Nos. WO 2008/103432 and WO 2008/103473, and in commonly-assigned U.S. Patent Application Publication No. 2007/0048315, the disclosures of which are hereby incorporated by reference in their entireties.
Antibodies for use in human subjects must be stored prior to use and transported to the point of administration. Reproducibly attaining a desired level of antibody drug in a subject requires that the drug be stored in a formulation that maintains the bioactivity of the drug. The need exists for formulations of anti-human IL-23p19 antibodies for use, e.g., in treatment of inflammatory, autoimmune, and proliferative disorders. Preferably, such formulations will exhibit a long half-life, be stable when stored and transported, and will be amenable to administration at high concentrations, e.g. for use in subcutaneous administration, and low concentrations, e.g. for intravenous administration.